contribution guidelines checks (#1787)

* spelling corrections

* review

* improved documentation, removed redundant variables, added testing

* added type hint

* camel case to snake case

* spelling fix

* review

* python --> Python # it is a brand name, not a snake

* explicit cast to int

* spaces in int list

* "!= None" to "is not None"

* Update comb_sort.py

* various spelling corrections in documentation & several variables naming conventions fix

* + char in file name

* import dependency - bug fix

Co-authored-by: John Law <johnlaw.po@gmail.com>

data_structures/binary_tree/binary_search_tree.py

@@ -28,16 +28,16 @@ class BinarySearchTree:
         """
         return str(self.root)
 
-    def __reassign_nodes(self, node, newChildren):
-        if newChildren is not None:  # reset its kids
-            newChildren.parent = node.parent
+    def __reassign_nodes(self, node, new_children):
+        if new_children is not None:  # reset its kids
+            new_children.parent = node.parent
         if node.parent is not None:  # reset its parent
             if self.is_right(node):  # If it is the right children
-                node.parent.right = newChildren
+                node.parent.right = new_children
             else:
-                node.parent.left = newChildren
+                node.parent.left = new_children
         else:
-            self.root = newChildren
+            self.root = new_children
 
     def is_right(self, node):
         return node == node.parent.right
@@ -117,39 +117,39 @@ class BinarySearchTree:
             elif node.right is None:  # Has only left children
                 self.__reassign_nodes(node, node.left)
             else:
-                tmpNode = self.get_max(
+                tmp_node = self.get_max(
                     node.left
-                )  #  Gets the max value of the left branch
-                self.remove(tmpNode.value)
+                )  # Gets the max value of the left branch
+                self.remove(tmp_node.value)
                 node.value = (
-                    tmpNode.value
-                )  #  Assigns the value to the node to delete and keesp tree structure
+                    tmp_node.value
+                )  # Assigns the value to the node to delete and keep tree structure
 
     def preorder_traverse(self, node):
         if node is not None:
-            yield node  #  Preorder Traversal
+            yield node  # Preorder Traversal
             yield from self.preorder_traverse(node.left)
             yield from self.preorder_traverse(node.right)
 
-    def traversal_tree(self, traversalFunction=None):
+    def traversal_tree(self, traversal_function=None):
         """
         This function traversal the tree.
         You can pass a function to traversal the tree as needed by client code
         """
-        if traversalFunction is None:
+        if traversal_function is None:
             return self.preorder_traverse(self.root)
         else:
-            return traversalFunction(self.root)
+            return traversal_function(self.root)
 
 
 def postorder(curr_node):
     """
     postOrder (left, right, self)
     """
-    nodeList = list()
+    node_list = list()
     if curr_node is not None:
-        nodeList = postorder(curr_node.left) + postorder(curr_node.right) + [curr_node]
-    return nodeList
+        node_list = postorder(curr_node.left) + postorder(curr_node.right) + [curr_node]
+    return node_list
 
 
 def binary_search_tree():

data_structures/binary_tree/number_of_possible_binary_trees.py

@@ -82,7 +82,7 @@ def binary_tree_count(node_count: int) -> int:
     """
     Return the number of possible of binary trees.
     :param n: number of nodes
-    :return: Number of possilble binary trees
+    :return: Number of possible binary trees
 
     >>> binary_tree_count(5)
     5040

data_structures/linked_list/deque_doubly.py

@@ -21,7 +21,7 @@ class _DoublyLinkedBase:
 
         def has_next_and_prev(self):
             return " Prev -> {0}, Next -> {1}".format(
-                self._prev != None, self._next != None
+                self._prev is not None, self._next is not None
             )
 
     def __init__(self):

data_structures/linked_list/doubly_linked_list.py

@@ -62,7 +62,7 @@ class LinkedList:  # making main class named linked list
 
     def display(self):  # Prints contents of the list
         current = self.head
-        while current != None:
+        while current is not None:
             current.displayLink()
             current = current.next
         print()

data_structures/queue/queue_on_list.py

@@ -1,4 +1,4 @@
-"""Queue represented by a python list"""
+"""Queue represented by a Python list"""
 
 
 class Queue: